Fuel injection regulator for internal combustion engines

ABSTRACT

A regulating arrangement for internal combustion engines, particularly of the diesel-engine type. The fuel injection pump is set and displaced through an amplifier having one signal input derived from a speed sensor coupled to the crank shaft of the engine. The input of amplifier may also be fed with a signal derived from the accelerating pedal of the engine. A hydraulic displacement device between the output of the amplifier and the fuel injection pump converts the electrical signal from the amplifier into a corresponding setting of the pump. The feedback network of the amplifier is such that the amplification of the amplifier is substantially high at idling speeds of the engine.

United States Patent [191 [111 3,724,430 I Adler 51 Apr. 3, 1973 [54]FUEL INJECTION REGULATOR FOR FOREIGN PATENTS OR APPLICATIONS INTERNALCOMBUSTION ENGINES [75] Inventor: Karl-Heinz Adler, Leonberg, Germany[73] Assignee: Robert Bosch GrnbH, Stuttgart, Ger- [22] Filed: Oct. 15,1969 [21] Appl. No.: 866,521

[52] US. Cl. ..123/32 EA, 123/119 R, 123/32 R [51] Int. Cl. ..F02b 3/00,F02b 33/00 [58] Field of Search ..123/32 CL; 60/3929 [56] ReferencesCited UNITED STATES PATENTS 2,886,015 5/1959 Steinke ..123/32 2,910,05410/1959 Schutte ..123/32 2,971,337 2/1961 Wintrode ..60/39.28 3,045,4267/1962 Brahm ..60/39.28 3,064,422 11/1962 Neher "60/3928 3,124,9323/1964 Nelson .....60/39.28 3,407,793 10/1968 Lang ..123/32 3,425,4012/1969 Lang ..123/32 3,526,212 9/1970 Bassot' ..123/32 3,028,526 4/1962Wintrode ..60/39.28 3,548,792 12/1970 Palmer ..123/32 CL PrimaryExaminer-Laurence M. Goodridge Attorney-Michael S. Striker [57] ABSTRACTA regulating arrangement for internal combustion engines, particularlyof the diesel-engine type. The fuel injection pump is set and displacedthrough an amplifier having one signal input derived from a speed sensorcoupled to the crank shaft of the engine. The input of amplifier mayalso be fed with a signal derived from the accelerating pedal of theengine. A hydraulic displacement device between the output of theamplifier and the fuel injection pump converts the electrical signalfrom the amplifier into a corresponding setting of the pump. Thefeedback network of the amplifier is such that the amplification of theamplifier is substantially high at idling speeds of the engine.

19 Claims, 6 Drawing Figures PATENTEDAPR 3 197a SHEET 2 [IF 2 l/VVENI'ORKarl-Heinz ADL ER FUEL INJECTION REGULATOR FOR INTERNAL COMBUSTIONENGINES BACKGROUND OF THE INVENTION The present invention resides in aregulating arrangement for internal combustion engines, particularly ofthe diesel type. The arrangement serves to regulate the amount of fuelinjected as a function of the rotational I speed of the engine and otherparameters, particularly the position of the accelerating level oraccelerating pedal.

Regulating arrangements are known which operate under principle ofcentrifugal-force regulators, or pneumatic and hydraulic speedregulating methods. In such arrangements, the regulator is directlycoupled with the displacement member for setting the amount of fuelinjected. These conventional arrangement which are known in the art, donot have sufficient displacement force or power at low rotational speedsof the engine, in viewof their inherent design. The regulators known inthe art, furthermore, are complex and massive, when provided withauxiliary force or driving power.

Accordingly, it is an object of the present invention to provide aregulator which does not have the preceding disadvantages.

The object of the present invention is achieved by providing theregulator for varying the quantity of fuel injected, in the form of a DCvoltage amplifier which has high amplification in the idling state ofthe engine. This amplifier has, furthermore, the desired regulatingcharacteristic through a corresponding feedback network.

With the arrangement of the present invention, the following advantagesare realized.

In such a regulator, the desired regulating charac teristics fordisplacement regulators and idling speed regulators may be designed wellthrough simple means by merely selecting the corresponding feedbacknetwork. Such regulators of the present invention, also may be adaptedreadily and simply to different types of engines. For this reason, theregulating arrangements are also very adapted for motor vehicle driving,especially since they are relatively insensitive to temperature. Byselecting the feedback network, furthermore, the timing relationship ofthe entire regulating circuit may be influenced.

SUMMARY OF THE INVENTION A regulating arrangement for internalcombustion engines, particularly those of the diesel type. A fuelinjection pump is set through a displacement member which may be of thehydraulic type and is equipped with a hydraulic piston coupled to theinput of the pump. The piston of the hydraulic displacement arrangementis controlled in its position through the actuation of flow valveswhich, in turn, are controlled by the output signal of a DC voltageamplifier. The inputs to the amplifier are derived from speedtransducers which apply to the amplifier signals as a function of thespeed of the engine. The input to the amplifier may also be operativelycoupled to the accelerating pedal of the engine. The feedback network ofthe amplifier is such that the amplifier has substantially highamplification at the idling speeds of the engine.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic block diagram ofthe regulating arrangement of the present invention;

FIG. 2 is a schematic block diagram of a speed transducing circuit usedin the regulating arrangement of FIG. 1;

FIG. 3 is an electrical schematic diagram of another embodiment of thespeed transducing arrangement of FIG. 2;

FIG. 4 is an electrical schematic diagram of a regulating unit used inthe arrangement of the present invention;

FIG. 5 is an electrical schematic diagram of a regulating unit withfeedback coupling network of the present invention; and

FIG. 6 is a functional schematic diagram and shows a regulating unit incombination with a hydraulic displacement arrangement for adjusting theamount of fuel injected into the engine, in accordance with the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, FIG.1 shows an internal combustion engine which is an element within aregulating circuit and to which a disturbing parameter is applied. Suchdisturbing parameter 2 may be due, for example, to the loading of themachine. As a result of this distributing parameter 2, the rotationalspeed it varies. Connected to the output of the internal combustionengine 10, is a transducer 11 which provides a first signal in the formof a voltage U, proportional to the rotational speeds n of the engine.This voltage U,, is applied to a regulator 12. A voltage U is alsoapplied to the regulator 12. This voltage U is derived from anelectromechanical transducer 13 which is mechanically coupled to theacceleration lever 14 or the gas pedal constituting signalling meansfurnishing second signals. The regulator 12 processes the actualrotational engine speed n and the desired speed as determined from theposition of the acceleration lever 14, and emits thereupon a signal tothe positioning member 15. Through this signal, an injection pump 16 isdisplaced or set through a regulating rod, not shown. With such settingor displacement of the pump 16, the quantity of fuel injected perstroke, and thereby the rotational speed of the engine 10, becomevaried. From the viewpoint of stability, it may advantage under certaincircumstances, to include the feedback arrangement 17 for applying theoutput of the positioning member 15 directly to the input thereof in afeedback group, and thereby stabilize the unit. Thus, the members 15 and17 can be comprised of, for example, a servo system with feedbackthrough which the signal derived from the regulator 12 is translatedinto mechanical motion for setting the injection pump 16.

FIGS. 2 and 3 show transducers which serve to apply to the regulator aDC voltage which corresponds to the rotational speeds n of the internalcombustion engine.

In the embodiment of FIG. 2, an inductive transducer 18 is driven by therotational speed of the engine and provides thereupon a pulsed signalwith frequency proportional to this rotational speed. The output of thetransducer 18 in the form of electrical pulses, is applied to a Schmitttrigger circuit 19 which serves the purpose of shaping the pulses sothat they have steep edges. The output of the Schmitt trigger circuit 19is then applied to a monostable multivibrator 20 which, when actuated,provides pulses having unity duration and amplitude. An R-C networkconnected to the output of the multivibrator 20 emits a DC voltage U,,which is proportional to the arithmetic average of the pulses generatedby the monostable multivibrator 20. The lower limit frequency of the R-Cnetwork 21 is determined through selected resistors and capacitors, sothat it is still above the highest regulating frequency of approximatelyHz.

FIG. 3 shows another embodiment for the transducer used to derive anelectrical signal proportional to the rotational speed. In thisembodiment, an alternating current rate generator 22 provides analternating voltage with amplitude dependent upon the rotational speed.The output of the rate generator is rectified through a rectifyingbridge 23, for example, and is then applied to an R-C network 24. Thevoltage U,, proportional to the rotational speed of the engine is takenfrom this R-C network. For realizing symmetrical behavior for increaseand decrease in the rotational speed, corresponding to charging anddischarging of the capacitor 25, it is essential that the internalresistance of the bridge 23 and the AC rate generator 22 be equal to theload resistance. This condition may be achieved by either winding therate generator 22 so that it has a high ohmic or resistance value, or bymaking the load resistance so that it is of low value. When resorting toa high resistance winding, an NTC resistor combination 26 can beprovided for temperature compensation of the rate generator votageoutput. This temperature compensation element 26 may be connectedbetween the output of the rate generator 22 and the bridge 23, andcompensates for the positive temperature coefficient of the copperwinding.

FIG. 4 shows the principle of the regulator. A DC voltage amplifier withhigh idling amplification is denoted by the reference numeral 27. Avoltage U,, proportional to the rotational speed n of the engine, isapplied to the first input 28 of this amplifier. The position of theacceleration lever 14, corresponding to the voltage U is applied to thesecond input 29 of the amplifier. The electromechanical transducer 13 iscomprised of a potentiometer having a resistance winding 30 to which areference voltage is applied for energizing the winding. The slidingcontact 31 of the potentiometer is positioned in accordance with theacceleration lever position 14, and the voltage output of the slidingcontact 31 is applied to the second terminal 29 of the amplifier 27,through an input resistor 32. The voltage U,, dependent upon therotational speed of the engine, is applied through an input resistor 33,to the first input terminal 28 of the amplifier. The resistor 33 may beof complex form, similar to that for the feedback resistor R.

Since the positioning member will often give rise to a delay in theregulating process, through which instabilities in the regulatingcircuit may result, it is often of advantage to include a differentialand/or integral element in the feedback network at the input of theregulator.

FIG. 5 discloses the details of the circuit for the DC voltage amplifier27. The voltage U, dependent upon the rotational speed of the engine isapplied through an R-C network and a resistor, to the first input of theDC amplifier 27. The R-C network may be contained within the speedtransducer. The feedback network R of the DC amplifier 27 is formed ofthe combination of two variable resistors 34 and 35 and a capacitor 36connected to the junction of these adjustable resistors. This feedbacknetwork also includes the combination of a capacitor 37 in parallel withthe windings of the two variable resistors, and a further variableresistor 38 with winding connected in parallel to the capacitor 37.Through the resistors 34 and 35, the proper stability for the regulatingcircuit is adjusted. The capacitor 37 is required for amplifierstabilization, and with the aid of the resistor 38, the desired settingof the regulator is realized.

FIG. 6 shows the arrangement of the regulator and the positioningelement 15 connected thereto. A discriminator 39 is connected in frontof this positioning element 15 in view of its three-point relationship.Depending upon the output signal of the regulator 12, either one or bothof the control valves 40 and 41 become actuated through thediscriminator 39. Another operating condition of these control valves isthat they are both in their quiescent or inoperative states. When thecontrol valve 40 becomes actuated, the pressurized fluid associated withthe positioning member or positioning element flows into the pressurechamber 42 and displaces the piston head 43 to which a regulating rod 45is secured. The pressure within the chamber 42 forces the piston 43towards the right against the action of the spring 44, and the resultingmotion of the regulating rod 45 serves to set the injection pump denotedby the reference numeral 16 in FIG. 1. With such setting of theinjection pump, for example, the amount of fuel introduced into theengine is increased. If, on the other hand, the control valve 41 becomesopened, the spring 44 moves pressingly the piston head 43 and therebythe regulating rod towards the left in the drawing. This results fromthe feature that the pressurized fluid is able to flow out of thechamber 42. The amount of fuel introduced into the engine becomesthereby reduced. When both valves 40 and 41 close, the positioningelement or displacement element is in its quiescent or inoperativestate.

In place of the hydraulic displacement element, an electrical motor canalso be provided, which moves the regulating rod 45 for the injectionpump either to the right or to the left as required.

Displacement members of that type require feedback of their output andto their input, in view of their integral behavior. For this reason, theregulating rod 45 is mechanically coupled to the sliding contact 46 of avariable resistor 47. The winding of this variable resistor is connectedto a reference voltage. The voltage value taken from the sliding contact46, is dependent upon the positioning of this contact and hence theposition of the regulating rod 45. This voltage from the sliding contact46 is then fed back to the three-point discriminator 39.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied inregulating arrangements for internal combustion engines, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. A regulating arrangement for an internal combustion engine,comprising, in combination, fuel injec' tion means for introducing fuelinto said engine as a function of a fuel-injection signal applied tosaid fuel injection means; speed sensing means coupled to said enginefor providing a first signal corresponding to the speed of said engine;signalling means for providing a second signal corresponding to adesired operating characteristic of said engine; direct-currentdifference amplifier means comprising an output connected with said fuelinjection means for applying thereto a fuel-injection signal; inputmeans comprising a pair of inputs respectively connected with said speedsensing means and with said signalling means; and feedback network meansconnected with said output means and said input means for synthesizing adesired characteristic functional relationship between the signals atsaid input means and the signals generated at said output, saiddifference amplifier means being operative for controlling operation ofsaid fuel injection means as a function of said first and second signalsand in accordance with said characteristic functional relationship.

2. The regulating arrangement as defined in claim 1, wherein saidfeedback means comprises passive electrical components.

3. The regulating arrangement as defined in claim 1, wherein said enginecomprises a diesel engine.

4. The regulating arrangement as defined in claim 1 wherein saidfeedback network means comprises means for diminishing delay times inthe response of the output signal of said amplifying means relative tothe input signal applied to said amplifying means.

5. The regulating arrangement as defined in claim 1 includingdisplacement means coupled to said fuel injection means and connected tosaid output of said amplifier means for setting said fuel injectionmeans to a predetermined position for introducing a predeterminedquantity of fuel into said engine.

6. The regulating arrangement as defined in claim 5 wherein saiddisplacement means comprises a hydraulic arrangement with two controlvalves actuated by said output of said amplifier means; a pressurechamber in which fluid flow is controlled through said control valves; adisplaceable piston communicating with said pressure chamber anddisplaced as a function of the pressure within said chamber; and pistonrod means connected between said piston head and said fuel injectionmeans for setting said fuel injection means so that a predeterminedquantity of fuel is introduced into said engine as a function of theposition of said piston.

7. The regulating arrangement as defined in claim 6 including athree-point discriminator connected between the output of saidamplifying means and-said control valves for actuating said valves.

8. The regulating arrangement as defined in claim 7 including variableresistor means with movable contact coupled to said piston rod andelectrical voltage output of said movable contact connected to saiddiscriminator for applying to said discriminator a feedback voltagedependent upon the output displacement of said piston rod.

9. The regulating arrangement as defined in claim 5, wherein saiddisplacement means comprises an electrical motor for displacing saidfuel injection means in one direction and alternatively in the oppositedirection dependent upon the quantity of fuel to be introduced into saidengine.

10. The regulating arrangement as defined in claim 1 includingdisplacement means with integral operating characteristic connected tothe output of said amplifier means; and feedback means connected betweenthe output and input of said displacement means.

1 1. The regulating arrangement as defined in claim 1 wherein said speedsensing means comprises an alternating current rate generator withoutput AC voltage having an amplitude proportional to the rotationalspeed of said engine; rectifying means connected to the output of saidalternating current rate generator for rectifying the voltage output ofsaid generator; and resistor-capacitor network means connected betweenthe output of said rectifier means and input of said amplifymg means.

12. The regulating arrangement as defined in claim 11 wherein theequivalent internal resistance of said rectifying means and said rategenerator is equal to the equivalent load resistance applied to saidrectifying means.

13. The regulating arrangement as defined in claim 12 including resistormeans with negative temperature coefficient connected to the output ofsaid alternating current rate generator for temperature compensating theoutput voltage of said generator against fluctuations due to variationsin the internal resistance of the winding of said generator due totemperature variations, said winding of said rate generator having asubstantially high electrical resistance.

14. The regulating arrangement as defined in claim 1 wherein said speedsensing means comprises a rate generator providing an alternatingcurrent with frequency dependent upon the rotational speed of saidengine; pulse shaping means connected to said rate generator andreceiving said alternating current signal for shaping said alternatingcurrent signal into a pulsed signal; and monostable multivibrator meansconnected to the output of said pulse shaping means for providingrectangular-shaped pulses dependent upon the rotational speed of saidengine.

15. The regulating arrangement as defined in claim 14, wherein saidpulse-shaping means comprises a Schmitt trigger circuit.

16. The regulating arrangement as defined in claim 14 including aresistor-capacitor network connected to the output of said monostablemultivibrator for converting rectangular-shaped pulses dependent uponsaid rotational speed of said engine into a DC voltage dependent uponsaid rotational speed, said DC voltage being applied to said one inputof said amplifier.

17. The regulating arrangement as defined in claim 16 including resistormeans connected between the output of said resistor-capacitor networkand said one input of said amplifier.

18. The regulating arrangement as defined in claim 16, wherein the lowerfrequency limit of said resistance-capacitor network is higher than thehighest regulating frequency 19. A regulating arrangement for aninternal combustion engine comprising, in combination, fuel injectionmeans for introducing fuel into said engine; speed sensing means coupledto said engine for providing a signal indicative of the speed of saidengine; and direct current operational amplifying means connectedbetween said fuel injection means and said speed sensing means forregulating said fuel injection means so that the quantity of fuelinjected into said engine is a function of the speed of said engine,said amplifying means having substantially high amplification at stallloads of said engine, said direct current operational amplifying meanscomprising a DC amplifier with feedback network, said feedback networkbeing comprised of passive electrical components, said feedback networkcomprising further an adjustable resistor connected between the outputand the input of said amplifier, a capacitor connected in parallel withthe resistance winding of said adjustable resistor, a combination of twoseries-connected resistors in parallel with said capacitor and saidadjustable resistor, and auxiliary capacitor means connected betweenground potential and the junction of said two series-connectedresistors.

1. A regulating arrangement for an internal combustion engine,comprising, in combination, fuel injection means for introducing fuelinto said engine as a function of a fuel-injection signal applied tosaid fuel injection means; speed sensing means coupled to said enginefor providing a first signal corresponding to the speed of said engine;signalling means for providing a second signal corresponding to adesired operating characteristic of saiD engine; direct-currentdifference amplifier means comprising an output connected with said fuelinjection means for applying thereto a fuel-injection signal; inputmeans comprising a pair of inputs respectively connected with said speedsensing means and with said signalling means; and feedback network meansconnected with said output means and said input means for synthesizing adesired characteristic functional relationship between the signals atsaid input means and the signals generated at said output, saiddifference amplifier means being operative for controlling operation ofsaid fuel injection means as a function of said first and second signalsand in accordance with said characteristic functional relationship. 2.The regulating arrangement as defined in claim 1, wherein said feedbackmeans comprises passive electrical components.
 3. The regulatingarrangement as defined in claim 1, wherein said engine comprises adiesel engine.
 4. The regulating arrangement as defined in claim 1wherein said feedback network means comprises means for diminishingdelay times in the response of the output signal of said amplifyingmeans relative to the input signal applied to said amplifying means. 5.The regulating arrangement as defined in claim 1 including displacementmeans coupled to said fuel injection means and connected to said outputof said amplifier means for setting said fuel injection means to apredetermined position for introducing a predetermined quantity of fuelinto said engine.
 6. The regulating arrangement as defined in claim 5wherein said displacement means comprises a hydraulic arrangement withtwo control valves actuated by said output of said amplifier means; apressure chamber in which fluid flow is controlled through said controlvalves; a displaceable piston communicating with said pressure chamberand displaced as a function of the pressure within said chamber; andpiston rod means connected between said piston head and said fuelinjection means for setting said fuel injection means so that apredetermined quantity of fuel is introduced into said engine as afunction of the position of said piston.
 7. The regulating arrangementas defined in claim 6 including a three-point discriminator connectedbetween the output of said amplifying means and said control valves foractuating said valves.
 8. The regulating arrangement as defined in claim7 including variable resistor means with movable contact coupled to saidpiston rod and electrical voltage output of said movable contactconnected to said discriminator for applying to said discriminator afeedback voltage dependent upon the output displacement of said pistonrod.
 9. The regulating arrangement as defined in claim 5, wherein saiddisplacement means comprises an electrical motor for displacing saidfuel injection means in one direction and alternatively in the oppositedirection dependent upon the quantity of fuel to be introduced into saidengine.
 10. The regulating arrangement as defined in claim 1 includingdisplacement means with integral operating characteristic connected tothe output of said amplifier means; and feedback means connected betweenthe output and input of said displacement means.
 11. The regulatingarrangement as defined in claim 1 wherein said speed sensing meanscomprises an alternating current rate generator with output AC voltagehaving an amplitude proportional to the rotational speed of said engine;rectifying means connected to the output of said alternating currentrate generator for rectifying the voltage output of said generator; andresistor-capacitor network means connected between the output of saidrectifier means and input of said amplifying means.
 12. The regulatingarrangement as defined in claim 11 wherein the equivalent internalresistance of said rectifying means and said rate generator is equal tothe equivalent load resistance applied to said rectifying means.
 13. Theregulating arrangement as defined in claim 12 inclUding resistor meanswith negative temperature coefficient connected to the output of saidalternating current rate generator for temperature compensating theoutput voltage of said generator against fluctuations due to variationsin the internal resistance of the winding of said generator due totemperature variations, said winding of said rate generator having asubstantially high electrical resistance.
 14. The regulating arrangementas defined in claim 1 wherein said speed sensing means comprises a rategenerator providing an alternating current with frequency dependent uponthe rotational speed of said engine; pulse shaping means connected tosaid rate generator and receiving said alternating current signal forshaping said alternating current signal into a pulsed signal; andmonostable multivibrator means connected to the output of said pulseshaping means for providing rectangular-shaped pulses dependent upon therotational speed of said engine.
 15. The regulating arrangement asdefined in claim 14, wherein said pulse-shaping means comprises aSchmitt trigger circuit.
 16. The regulating arrangement as defined inclaim 14 including a resistor-capacitor network connected to the outputof said monostable multivibrator for converting rectangular-shapedpulses dependent upon said rotational speed of said engine into a DCvoltage dependent upon said rotational speed, said DC voltage beingapplied to said one input of said amplifier.
 17. The regulatingarrangement as defined in claim 16 including resistor means connectedbetween the output of said resistor-capacitor network and said one inputof said amplifier.
 18. The regulating arrangement as defined in claim16, wherein the lower frequency limit of said resistance-capacitornetwork is higher than the highest regulating frequency.
 19. Aregulating arrangement for an internal combustion engine comprising, incombination, fuel injection means for introducing fuel into said engine;speed sensing means coupled to said engine for providing a signalindicative of the speed of said engine; and direct current operationalamplifying means connected between said fuel injection means and saidspeed sensing means for regulating said fuel injection means so that thequantity of fuel injected into said engine is a function of the speed ofsaid engine, said amplifying means having substantially highamplification at stall loads of said engine, said direct currentoperational amplifying means comprising a DC amplifier with feedbacknetwork, said feedback network being comprised of passive electricalcomponents, said feedback network comprising further an adjustableresistor connected between the output and the input of said amplifier, acapacitor connected in parallel with the resistance winding of saidadjustable resistor, a combination of two series-connected resistors inparallel with said capacitor and said adjustable resistor, and auxiliarycapacitor means connected between ground potential and the junction ofsaid two series-connected resistors.